Cold-formable chrome steel

ABSTRACT

A cold-formable, corrosion-resistant chrome steel includes, by weight percent, 14% to 20% chromium, 0.005% to 0.05% carbon, up to 0.01% nitrogen, 0.2% to 0.6% silicon, 0.3% to 1.0% manganese, 0.1% to 1.0% molybdenum, up to 0.8% nickel, 0.2% to 1.0% copper, 0.15% to 0.65% sulfur, as well as separately or in combination 0.01% to 0.1% lead, 0.01% to 0.5% bismuth, 0.01% to 0.1% arsenic, 0.01% to 0.1% antimony, 0.005% to 0.08% of each of vanadium, titanium, niobium, and zirconium, 0.02% to 0.2% of each of selenium and tellurium, the remainder iron and incidental smelting-related impurities.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a continuation of prior filed copending U.S.application Ser. No. 11/049,617, filed Feb. 2, 2005, which claims thepriority of German Patent Applications, Serial Nos. 10 2004 015992.0-24, filed Apr. 1, 2004, and 10 2004 063 161.1, filed Dec. 29,2004, pursuant to 35 U.S.C. 119(a)-(d).

The content of U.S. application Ser. No. 11/049,617 is incorporatedherein by reference in its entirety as if fully set forth herein

BACKGROUND OF THE INVENTION

The present invention relates to a cold-formable chrome steel with aferritic structure.

Nothing in the following discussion of the state of the art is to beconstrued as an admission of prior art.

Without the implementation of special alloying procedures, cold-formableand corrosion-resistant ferritic chrome steels have poor machiningproperties, mostly due to sticking and welding that occurs duringmachining in the region of sharp tool edges. The cutting edge can thenbecome jagged and can splinter, the tool may wear poorly, and thesurface quality of the machined workpieces may be poor.

Sticking and welding may also be detrimental when using stamping andforming tools, because these processes occur predominantly in the regionof high surface pressure, thus diminishing the surface quality of themachined workpieces and shortening the service life of the tools. Inaddition to an adequate machining and processing ability, the steelsshould also have a certain minimum rigidity that is only achievable byincorporating in the alloy certain additives that, like titanium,vanadium, niobium, zirconium, and molybdenum, form carbides andcarbo-nitrides. These are present in the structure as hard precipitatephases with a low solubility and tend to build up locally in thestructure, forming agglomerates, clusters or cellular structures.

This increases the risk that during micro-machining, for example whendrilling bore holes, grooves and recesses with small to extremely smalldimensions, the tool, for example a drill, runs off center, caused bythe local concentration of hard precipitate phases, thus causingsubstantial deviations in the final dimensions. This is caused by thefact that the machining tools, for example a small diameter drill, tendto migrate away from areas with greater hardness or greater carbideconcentration. Even the use of micro-tools or drills made of high-gradehard metals, for example with a diameter of less than 0.8 mm, cannotprevent tool runoff, because the tool is diverted from the predeterminedmachining direction by regions of high concentration of structuralcarbide components.

Steels of the afore-described type are known in the art. They haveexcellent magnetizability, like the soft-magnetic chrome steel describedin U.S. Pat. No. 4,714,502, which includes up to 0.03% carbon, up to0.40 to 1.10% silicon, up to 0.50% manganese, 9.0 to 19% chromium, up to2.5% molybdenum, up to 0.5% nickel, up to 0.5% copper, 0.02 to 0.25%titanium, 0.010 to 0.030% sulfur, up to 0.03% nitrogen, 0.31 to 0.60%aluminum, 0.10 to 0.30% lead, and 0.02 to 0.10% zirconium. The steel isrust-free and cold-formable, and can be employed in the fabrication ofcores for solenoid valves, electromagnetic couplings or housings forelectronic injection systems for internal combustion engines.

Another soft-magnetic rust-free chrome steel with up to 0.05% carbon, upto 6% silicon, 11 to 20% chromium, up to 5% aluminum, 0.03 to 0.40%lead, 0.001 to 0.009% calcium, and 0.01 to 0.30% tellurium is disclosedin U.S. Pat. No. 3,925,063. This steel can be easily machined due to thepresence of lead, calcium and tellurium.

However, the relatively high silicon, aluminum and titanium content inthe steel produces hard oxide inclusions which causes severe wear duringprecision machining. A relatively high lead concentration of 0.03 to0.40% is incorporated to neutralize this effect. Disadvantageouslyhowever, lead has a very low melting point and therefore does not formstable compounds or precipitates. Lead also has an extremelyinhomogeneous distribution in the structure.

The German laid-open application 101 43 390 A1 describes a cold-formablecorrosion-resistant ferritic chrome steel with the 0.005% to 0.01%carbon, 0.2% to 1.2% silicon, 0.4% to 2.0% manganese, 8% to 20%chromium, 0.1% to 1.2% molybdenum, 0.01% to 0.5% nickel, 0.5% to 2.0%copper, 0.001% to 0.6% bismuth, 0.002% to 0.1% vanadium, 0.002% to 0.1%titanium, 0.002% to 0.1% niobium, 0.15% to 0.8% sulfur, and 0.001% to0.08% nitrogen, remainder iron, including smelting-related impurities.This chrome steel, due to its excellent machinability, in particular itsexcellent metal-cutting properties, excellent wear resistance andsurface quality, is a suitable material for precision-mechanicalapplications and precision devices, in particular for spinnerets andspray nozzles, as well as for writing utensils, jewel stylus and printheads.

It would therefore be desirable and advantageous to produce a ferriticchrome steel that can not only be cut without causing sticking andwelding, but which can also be micro-machined with a preciselymaintained directional accuracy.

SUMMARY OF THE INVENTION

According to one aspect of the present invention, a. chrome steel alloyaccording includes by weight percent 14% to 20% chromium, 0.005% to0.05% carbon, up to 0.01% nitrogen, 0.2% to 0.6% silicon, 0.3% to 1.0%manganese, 0.1% to 1.0% molybdenum, up to 0.8% nickel, 0.2% to 1.0%copper, 0.02% to 0.2% selenium, and further at least one of 0.01% to0.1% lead, 0.01% to 0.5% bismuth, 0.01% to 0.1% arsenic, 0.01% to 0.1%antimony, 0.005% to 0.08% vanadium, 0.005% to 0.08% titanium, 0.005% to0.08% niobium, 0.005% to 0.08% zirconium, 0.15% to 0.65% sulfur, up to0.20% tellurium, the remainder iron and incidental smelting-relatedimpurities.

According to one advantageous composition, the chrome steel alloy mayinclude by weight percent 14% to 18% chromium, 0.01% to 0.03% carbon, upto 0.01% nitrogen, 0.3% 0.5% silicon, 0.4% to 0.7% manganese, 0.1% to0.6% molybdenum, up to 0.5% nickel, 0.2% to 0.6% copper, 0.02% to 0.2%selenium, and further at least one of 0.01% to 0.05% lead, 0.01% to 0.3%bismuth, 0.01% to 0.05% arsenic, 0.01% to 0.05% antimony, 0.005% to0.08% vanadium, 0.005% to 0.08% titanium, 0.005% to 0.08% niobium,0.005% to 0.08% zirconium, 0.15% to 0.65% sulfur, 0.01% to 0.2%tellurium, the remainder iron and incidental smelting-relatedimpurities.

The material properties can be optimized, if the composition of thesteel alloy satisfies at least one of the following conditions:

K1=(% Ti+% V+% Nb+% Zr)/(% C)=3 to 12

K2=(% S+3% Se+3% Te)/10·(% C++% N)=1.5 to 3.5

K3=(% S)/(% S+% Se+% Te)=0.68 to 0.98

The simultaneous presence of sulfur, selenium and tellurium has aparticularly beneficial effect on the material properties due to thepresence of fine precipitates of sulfide, selenide and telluride, aslong as the corresponding concentrations of these elements satisfy thecondition for K3.

According to an advantageous feature of the invention, after at leastone cold forming process with a deformation of a total of 65% to 90%,the steel alloy can be annealed for 30 to 60 minutes at 750 to 1080° C.The steel can then be cooled within 30 to 180 minutes from the annealingtemperature to a temperature of 700° C. to 500° C. by supplying a smallamount of energy.

Advantageously, during the cooling process, the temperature of the steelis held at a constant value at least once for 10 to 30 minutes.

A chrome steel according to the present invention is suitable because ofits cold-formability and machining capabilities, in particular itsexcellent metal-cutting properties, its homogeneous structure and thehomogeneous distribution of the precipitate phases after cold-formingand following annealing with controlled cool-down, for the manufactureof printer nozzles, tips for writing implements, injection nozzles forchemical and electronic devices, spinnerets, as well as other articlesof small dimensions and/or recesses, in particular bore holes.

BRIEF DESCRIPTION OF THE DRAWING

Other features and advantages of the present invention will be morereadily apparent upon reading the following description of currentlypreferred exemplified embodiments of the invention with reference to theaccompanying drawing, in which:

FIG. 1 shows the heat of formation of exemplary metal sulfides andselenides;

FIG. 2 shows a schematic diagram of the concentration of an element in aprecipitate;

FIG. 3 shows a schematic diagram of the concentration of an element anda corresponding lubricant zone;

FIG. 4 shows a micrograph of a chrome steel alloy with precipitates;

FIG. 5 shows schematically temperature curves during annealing andcool-down;

FIG. 6 illustrates probing of a drilled hole with a test pin;

FIG. 7 shows a micrograph of a smooth bore hole; and

FIG. 8 shows a micrograph of a bore hole with jagged edges.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Throughout all the Figures, same or corresponding elements are generallyindicated by same reference numerals. These depicted embodiments are tobe understood as illustrative of the invention and not as limiting inany way. It should also be understood that the drawings are notnecessarily to scale and that the embodiments are sometimes illustratedby graphic symbols, phantom lines, diagrammatic representations andfragmentary views. In certain instances, details which are not necessaryfor an understanding of the present invention or which render otherdetails difficult to perceive may have been omitted.

The mechanical properties of the steel of the invention aresignificantly affected not only by the presence of certain precipitatephases, but even more so by their physical properties and distributionin the structure. The structure therefore includes metal sulfides aswell as metal selenides, which in turn interact with carbides andthio-carbides to improve the chip breaking characteristic. With theinvention, certain alloy elements are set free in the region near theprecipitates by rearrangement and exchange interactions so as tosurround the hard precipitates with a lubricant zone of consisting ofmetals and/or metal compounds which then act as lubricant zones andimprove the machining properties.

Precipitates of sulfides, selenides or tellurides or mixtures thereof,but also precipitates resulting from rearrangement or exchange reactionswith carbides, are produced at different temperatures in the solid phaseof the steel alloy. When the melt cools down, so-called primaryprecipitates are formed which subsequently grow and coarsen. Accordingto the invention, certain elements, such as lead and/or bismuth and/orarsenic and/or antimony and/or vanadium, titanium, niobium, as well aszirconium, are combined with the precipitate formers carbon, nitrogen,sulfur, selenium and tellurium, producing a large number of possiblereactions that can prevent the detrimental growth of these primaryprecipitates.

Turning now to the drawing, and in particular to FIG. 1, there is showna diagram with exemplary heat of formation values for important sulfidesand selenides which are significant for the invention. Precipitates areformed only if the thermodynamic conditions are favorable, with the heatof formation being an important predictor. Because all these metalcompounds have a negative heat of formation, thermodynamically stableprecipitates can form. A more negative heat of formation of a certainprecipitate indicates that this precipitate is more likely to form.

In the steel alloy of the invention, the non-metallic precipitateformers carbon, sulfur, selenium, tellurium and optionally nitrogen, areonly present in low concentrations so as to prevent supersaturation,because otherwise rapidly growing coarse precipitates could form, whichwould be difficult to reduce in grain size or completely dissolve. A lowcarbon concentration appears to be of particular significance for movingthe reaction equilibrium to promote formation of sub-stoichiometriccarbides.

Because the precipitates mainly form during cooling, diffusion effects(solid state diffusion in steel alloys) play an important role duringthe formation and growth of the precipitates. In general, elements witha small atomic mass diffuse more easily and faster than heavy atoms.Carbide and nitride precipitates, also referred to as so-called primaryprecipitates, are therefore readily generated in steel alloys. Sulfidesand/or selenides and other precipitates, such as thio-carbides andthio-carbo-selenides, are only formed after precipitation of the primaryprecipitates.

Sub-stoichiometric carbon-deficient primary carbides can be produced dueto the low carbon concentration. This carbon deficiency is compensatedthrough diffusion of carbon only after an extended period of time;carbon can also be partially replaced by sulfur or selenium.

The sub-stoichiometric primary carbides are produced, for example,according to the equation

Me¹+xC→Me¹Cx  (1)

wherein Me¹ refers to the elements titanium, vanadium, niobium andzirconium, and x is the stoichiometric factor. However, these elementscan also react with nitrogen, sulfur and selenium (tellurium), formingthio-carbides, thio-selenides or thio-carbo-selenides.Sub-stoichiometric precipitates therefore remain active after thesecompounds have been formed.

The composition of the primary carbides (or primary precipitates) of theMe¹-metals can vary over a wide range without adversely affecting thelattice structure of the precipitates. It is known from publishedreferences that, for example, titanium carbide forms stable alloys overa wide range from TiC_(0.22) to TiC_(1.0). For example, for astoichiometric factor of for example x=0.5, the equation 1 for titaniumcould be written as:

Ti+0.5C→TiC_(0.5)  (1a)

Due to their position in the periodic system, sulfur, selenium and alsotellurium show similar reactions, which is also evident from thethermodynamic numbers listed in Table I. The elements copper, lead,arsenic, antimony and manganese are important for forming precipitatesby reacting with sulfur, selenium and tellurium; they have to bedifferentiated from the Me^(I)-metals and will subsequently be referredto as Me^(II)-metals.

Typical reaction equations with sulfur and selenium include:

Me^(II)+S→Me^(II)S  (2)

and

Me^(II)+Se→Me^(II)Se  (3)

Unlike the Me¹ elements, they do not form carbides, carbo-nitrides orthio-carbides.

All precipitates typically form so-called depletion zones in theirimmediate vicinity, which are produced when from the matrix thoseelements are removed by diffusion that are required for producing aprecipitate and incorporated in the precipitate. This results in aconcentration dependence of the elements depicted in the diagrams ofFIGS. 2 and 3.

FIG. 2 shows schematically the spatial distribution of the concentrationof an element in a precipitate 1. The element has an averageconcentration c^(i) _(M) in the matrix which increases to aconcentration c^(i) _(A) in the precipitate. A depletion zone with widthD forms around the precipitate, which itself has a size R. FIG. 3 showsagain the concentration c1 of an element in a precipitate, wherein thistime the precipitate is surrounded by a lubricant zone 2 with aconcentration c2 of the lubricant.

Because these depletion zones hinder the desired rearrangement andexchange reactions between the precipitates, the invention recommendsspecific measures for minimizing the depletion zones. These measuresinclude, in combination, cold-forming and heat treatment which causerearrangement and exchange reactions between primary and secondaryprecipitates.

Already generated precipitates are then dissolved and new precipitatesare formed; however, copper can also be set free that acts in thevicinity of the primary precipitates as a lubricant. Becauserearrangement reactions take place predominantly during the coolingcycle, the precipitates are necessarily very fine-grained. Sufficienttime should be allocated for rearrangement reactions, because thematerial transport that plays a role in the rearrangement reactionsoccurs by diffusion. Advantageously, a slow cool-down and/or soakingtimes at 700 to 500° C. and/or a subsequent heat treatment can beimplemented.

The rearrangement and exchange reactions between sub-stoichiometriccarbide Me¹-precipitates and one or more sulfide and/or selenidesprecipitates presumably take place by release of the elements.

An exemplary reaction of a sub-stoichiometric precipitate with a sulfide(in this case copper sulfide) could be written for TiC_(0.5) as:

4TiC_(0.5)+2CuS→Ti₄C₂S₂+2Cu  (4)

Because the sulfur of the copper sulfide reaches the lattice of thethio-carbide (Ti₄C₂S₂) through diffusion, copper is released thatprecipitates in the immediate vicinity of the hard titaniumcarbo-sulfide precipitate. The released elements, in this case copper,acts as a lubricant during machining. Similar reactions also take placebetween the other Me¹ precipitates and Me^(II)-sulfides or -selenides(for example, with precipitates of manganese and lead).

Dissolution reactions according to equation 4 are important, becausethey advantageously dissolve or etch coarse or linearly arrayedMe^(II)-sulfides (for example manganese sulfide), forming new, extremelyfine microscopic precipitates according to equation 4. The chrome steelof the invention therefore has a structure with a large number of fineprecipitates (FIG. 4).

Advantageously, according to the afore-described reaction equations, thefollowing conditions should exist to facilitate sufficiently fast andunconstrained re-dissolution and release reactions:

-   -   The length of the diffusion paths between the different        precipitates should be as short as possible to achieve fast        reaction times;    -   The number and/or size of the depletion zones in the regions        near the precipitates should be reduced to enhance the        reactivity of the precipitates;    -   The effect of the reaction temperatures and reaction times        should be adjusted so that the reactions, for example according        to equation 3, occur over a short time.

According to the invention, the steel should therefore be initiallysubjected to one or more severe deformations to introduce dislocationsand to better mix the components of the structure. At the same time, theseparation between the precipitates is advantageously changed and thesize of the depletion zones is reduced. The severe deformations alsoshorten the diffusion paths, which again significantly increases thereactivity.

In order to enable the re-dissolution and release reactions to takeplace with sufficient speed, the preferably cold-formed steel isannealed at temperatures from T₁=750° C. to T₂=1080° C. (see FIG. 5). Inthis range, the re-dissolution and release reactions take place underformation of new precipitates, possibly having a new composition,similar to the reaction described in equation 4 above. According to theinvention, a final annealing step can be performed at temperatures notexceeding 450° C. in order to solidify released lubricant metals ornewly formed very fine precipitates, to harden in the steel matrix, toreduce strain, and to adjust the hardness or stability of the steelalloy. The hardness can progressively decrease during the finalannealing step, if the temperature is above approximately 350° C., whichsuggests a loss of cohesion of the matrix.

Preferably, after at least one cold-forming step with a deformation ofmore than 65%, the steel is annealed for 30 to 60 minutes at atemperature of 750° C. to 1080° C. (curve 3) and thereafter controllablycooled down for 30 to 180 minutes to a temperature T₂ from 500° C. to700° C., while supplying a small amount of energy (FIG. 5). Theprecipitates produced during the annealing are thereby stabilized bycontrolled diffusion. Advantageously, the steel is held steady at leastonce at one or more intermediate temperatures of, for example, 680° C.during the cooling step by briefly supplying more heat (FIG. 5, equation4).

The invention will now be described in more detail with reference tocertain illustrated embodiments.

Table I lists the composition of three exemplary alloys E1 to E3according to the invention and of eight comparative alloys V1 to V8.Table II lists the corresponding K1, K2, and K3 values as well as theresults of the machining tests. BV represents a characteristic value forthe drilling path, BG for the burr width, and BWG a characteristic valuefor the surface quality.

Example 1

After an etching step, a bare wire having the composition E2 with adiameter of 6 mm was initially subjected to a 3-stage cold-formingprocess producing a total deformation of 85%. The wire was then annealedin an inert gas atmosphere for 30 minutes at a temperature T₁=840° C.(see FIG. 5, curve 3) and thereafter controllably cooled down over 120minutes to a temperature of T₂=600° C. During the cool-down step, anintermediate 15 minute intermediate heating step was applied twice atrespective temperatures of 760° C. and 680° C., while maintaining aconstant temperature, to attain a stepped cool-down for stabilizing theprecipitates (see FIG. 5, curve 4 a).

After the controlled cool-down, the wire was cooled in air (see FIG. 5,upper curve 5) without supplying additional energy and thereafter sized,which resulted in a deformation of 15%. Sizing was followed by a 15minute final annealing or tempering at 340° C. The wire had an excellentmachinability with micro-tools.

Example 2

A bare wire having the composition E3 and a diameter of also 6 mm wassubjected to a 3-stage cold-forming process producing a totaldeformation of 80%. The wire was then annealed in an inert gasatmosphere for 35 minutes at a temperature of T₁=900° C. (see FIG. 5,curve 3) and then controllably cooled down over 160 minutes at aconstant cooling rate, while supplying a small amount of energy, to atemperature T₂=620° C. (see FIG. 5, curve 4). The wire was then furtherdown cooled in air to room temperature (see FIG. 5, lower curve 5). Thewire was then sized with a deformation of 20% and soaked for 30 minutesat 280° C. and subjected after soaking to micro-cutting, yielding theresults listed in Table II.

The cutting performance was experimentally tested by drilling with ahard alloy drill bit with a diameter of 0.6 mm. The following testswhere performed:

-   -   The machining characteristic was evaluated based on the        straightness of the bore hole and assigned a parameter value BV,    -   The burr width at the edge of the bore was evaluated and        assigned a parameter value BG, and    -   The smoothness of the wall of the bore was evaluated        microscopically and assigned a parameter value BWG.

The straightness of the micro-bores was determined from the insertiondepth of a steel pin according to the diagram of FIG. 6. The insertiondepth E for a straight test pin was assumed to correspond to thestraight section of the bore, and the parameter value BV, whichdescribes the path of the bore, was determined as a ratio from theequation

BV=1−E/L,

wherein L is the total depth of the bore. A value BV=0 indicates thatthe bore is perfectly straight.

In addition, the burr width BG at the edge of the bore was measured atan angle between 20° and 30°.

Finally, the machinability was determined microscopically based on theextent and the frequency of cracking and jagging in the interior of thebore, resulting in a characteristic parameter value for BWG between 1and 4. A value BWG=1 indicates a perfect bore, whereas a value BWG=4 isindicative of severe cracks. The micrograph of FIG. 7 of test sample E2shows a smooth bore with a value BWG=1. Conversely, the micrograph ofFIG. 8 of the comparative sample V8 shows a bore with numerous cracksand a value BWG=4.

While the invention has been illustrated and described in connectionwith currently preferred embodiments shown and described in detail, itis not intended to be limited to the details shown since variousmodifications and structural changes may be made without departing inany way from the spirit of the present invention. The embodiments werechosen and described in order to best explain the principles of theinvention and practical application to thereby enable a person skilledin the art to best utilize the invention and various embodiments withvarious modifications as are suited to the particular use contemplated.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended claims and includes equivalents of theelements recited therein:

TABLE I Alloy C Si Mn S Cr Ni Mo Ai N V Ti Nb Zr Cu Bi Pb As Sb Se Te E10.008 0.63 0.42 0.26 17.34 0.24 0.21 0.003 0.006 0.06 0.01 0.012 0.0080.40 0.002 0 0 0.002 0.05 0 E2 0.012 0.72 0.36 0.29 16.52 0.12 0.270.002 0.007 0.04 0.01 0.008 0.01 0.37 0.005 0.008 0.1 0 0.06 0 E3 0.0200.65 0.75 0.31 17.60 0.10 0.23 0.002 0.004 0.05 0.02 0.01 0.01 0.63 0.010 traces 0.002 0.03 0 V1 0.033 0.5 1.0 0.48 13.50 0.11 0.10 0.004 0.0090.01 0.045 0.02 0 0.8 0.20 0 0 0 0 0 V2 0.008 0.82 0.5 0.22 17.05 0.120.45 0.003 0.008 0.003 traces 0 0 0 0 0 0 0 0 0 V3 0.015 0.45 0.42 0.0315.20 0.10 0.08 0.002 0.008 0.002 0.30 0 0 0 0 0 0 0 0 0 V4 0.015 0.650.52 0.004 18.00 0.15 0.02 0.003 0.015 0.005 0.35 0 0 0 0 0 0 0 0 0 V50.012 0.55 0.85 0.03 14.60 0.15 0.05 0.003 0.010 0.02 0.22 0.012 0 0.230.08 0 0 0 0 0 V6 0.090 0.32 0.38 0.002 12.45 0.15 0.05 0.002 0.028 00.008 0 0 traces 0 0 traces 0.02 0 0 V7 0.012 0.48 1.76 0.25 20.11 0.251.84 0.003 0.010 0 0.005 0.020 0.01 0.02 0 0.12 0.02 0 0 0 V8 0.040 0.601.62 0.03 18.40 8.60 0.02 0.003 0.072 0.020 0.010 0 0 3.00 0 0.12 0.02traces 0 0

TABLE II Mechanical Micro-Machining BV = 1 Alloy K1 K2 K3 E/I BG/mm BWGSuitability E1 11.25 2.93 0.84 0.00 0.03 1 very good E2 5.67 2.47 0.830.00 0.05 1 very good E3 4.50 1.67 0.91 0.05 0.08 1 good E4 5.20 1.870.89 0.00 0.04 1 very good E5 4.00 2.34 0.82 0.00 0.03 1 very good V12.27 1.14 1.00 0.58 0.24 3 very good V2 0.38 1.38 1.00 0.65 0.28 3 poorV3 20.13 0.13 1.00 0.83 0.14 4 very poor V4 23.67 0.01 1.00 0.77 0.12 4poor V5 21.00 0.14 1.00 0.55 0.21 3 poor V6 0.09 0.00 1.00 0.78 0.19 4poor V7 2.92 1.14 1.00 0.61 0.28 2 poor V8 0.75 0.03 1.00 0.68 0.32 4very poor

1. A chrome steel alloy having a composition comprising, by weightpercent, 14% to 20% chromium, 0.005% to 0.05% carbon, up to 0.01%nitrogen, 0.2% to 0.6% silicon, 0.3% to 1.0% manganese, 0.1% to 1.0%molybdenum, up to 0.8% nickel, 0.2% to 1.0% copper, 0.02% to 0.2%selenium 0.15% to 0.65% sulfur, 0.01% to 0.1% arsenic, 0.005% to 0.08%vanadium, and at least one element selected from the group consisting of0.01% to 0.1% lead, 0.01% to 0.5% bismuth, 0.01% to 0.1% antimony,0.005% to 0.08% titanium, 0.005% to 0.08% niobium, 0.005% to 0.08%zirconium, up to 0.20% tellurium, and any combination thereof, theremainder iron and incidental smelting-related impurities.
 2. The chromesteel alloy of claim 1, having, by weight percent, 14% to 18% chromium,0.01% to 0.03% carbon, up to 0.01% nitrogen, 0.3% to 0.5% silicon, 0.4%to 0.7% manganese, 0.1% to 0.6% molybdenum, up to 0.5% nickel, 0.2% to0.6% copper, 0.02% to 0.2% selenium, 0.15% to 0.65% sulfur, 0.01% to0.05% arsenic, 0.005% to 0.08% vanadium, and at least one elementselected from the group consisting of 0.01% to 0.05% lead, 0.01% to 0.3%bismuth, 0.01% to 0.05% antimony, 0.005% to 0.08% titanium, 0.005% to0.08% niobium, 0.005% to 0.08% zirconium, 0.01% to 0.2% tellurium, andany combination thereof, the remainder iron and incidentalsmelting-related impurities.
 3. The chrome steel alloy of claim 1,satisfying the following conditionK1=(% Ti+% V+% Nb+% Zr)/% C=3 to
 12. 4. The chrome steel alloy of claim1, satisfying the following conditionK2=(% S+3% Se+3% Te)/10(% C+% N)=1.5 to 3.5.
 5. The chrome steel alloyof claim 1, satisfying the following conditionK3=% S/(% S+% Se+% Te)=0.68 to 0.98.
 6. A method of using a chrome steelalloy according to claim 1 for producing an article to be machined witha cutting tool.
 7. The method of claim 6, wherein the cutting toolincludes a micro-cutting tool.
 8. A method of using a chrome steel alloyaccording to claim 1 for producing an article selected from the groupconsisting of printer nozzles, writing stylus, injection nozzles forchemical and electronic devices, spinnerets, and articles of small sizewith or without recesses.
 9. An article for industrial use having afeature size of 0.6 mm or less and being made from a chromium steelalloy having a composition according to claim
 1. 10. A chrome steelalloy having a composition comprising, by weight percent, 14% to 20%chromium, 0.005% to 0.05% carbon, up to 0.01% nitrogen, 0.2% to 0.6%silicon, 0.3% to 1.0% manganese, 0.1% to 1.0% molybdenum, up to 0.8%nickel, 0.2% to 1.0% copper, 0.02% to 0.2% selenium 0.15% to 0.65%sulfur, 0.01% to 0.1% arsenic, 0.005% to 0.08% vanadium, 0.01% to 0.1%antimony, and at least one element selected from the group consisting of0.01% to 0.1% lead, 0.01% to 0.5% bismuth, 0.005% to 0.08% titanium,0.005% to 0.08% niobium, 0.005% to 0.08% zirconium, up to 0.20%tellurium, and any combination thereof, the remainder iron andincidental smelting-related impurities.
 11. The chrome steel alloy ofclaim 10, having, by weight percent, 0.01% to 0.05% antimony.